Effects of Organo-Mineral Fertilizers on Nitrogen, Phosphorus, and Potassium Uptake in Tea (Camellia sinensis L.) under Acidic Highland Soils in Mufindi, Tanzania

Abstract

Tea (Camellia sinensis L. O. Kuntze) is a globally important beverage crop that requires high inputs of nitrogen (N), phosphorus (P), and potassium (K) to sustain optimum yield and quality. However, tea is commonly grown in strongly acidic soils where nutrient availability and uptake efficiency are constrained by nutrient fixation, leaching, and low nutrient retention. Organo-mineral fertilizers (OMFs), which combine organic and inorganic nutrient sources, may improve nutrient availability and fertilizer use efficiency under such conditions, but their effectiveness in Tanzanian tea-growing soils remains poorly understood. This study evaluated the effects of three FOMI Chai OMF formulations on N, P, and K uptake in clonal tea under strongly acidic soil conditions (pH 4.86) at Ngwazi Tea Research Station, Mufindi, Tanzania, during 2024–2025. Three formulations—FOMI Chai, FOMI Chai+, and FOMI Chai++—were applied at 100, 150, and 200 kg N ha-1, generating nine treatments (T1–T9) alongside a standard inorganic NPK fertilizer (TP) and an unfertilized control (TN) in a randomized complete block design with three replicates. Fertilizer type significantly affected N and K uptake (p < 0.001) and P uptake (p = 0.044), while application rate had no significant effect (p > 0.05). FOMI Chai++ produced the highest N, P, and K uptake, exceeding the standard inorganic fertilizer by 38.7%, 69.6%, and 33.5%, respectively. The results suggests that organo-mineral fertilizers had influence on nutrient uptake than the application rate within the tested range.